Magnetic structure for use in ion-traps



May 8, 1951 G. .1. MUCHER MAGNETIC STRUCTURE FOR USE IN ION TRAPS FiledFeb. 3, 1949 INVENTOR. 760] e [father ATTORNEYS Patented May 8, 1951MAGNETIC STRUCTURE. FOR USE IN ION-TRAPS George J. Mueller, Brooklyn, N.Y., assignor to Clarostat Mfg. 00., Inc., Brooklyn, N. Y., a corporationof New York Application February 3, 1949, Serial No. 74,291

9 Claims. 1

This invention relates to electronic apparatus, and particularly to whatis known in the cathode ray tube art as an ion trap.

The kinescope, which is a form of cathode ray tube which comprises theviewing tube in a television receiver, is costly; and it is ofimportance to prevent the bombardment of the viewing screen by ions,which are materially heavier than electrons and are capable of damagingthe screen coating. In the past, relatively complicated magnetic trapshave been utilized to deflect the ions so that they will be dissipatedagainst the neck or barrel portion of the tube before striking thefluorescent screen.

The present invention concerns an ion trap which is inexpensive tomanufacture, easy to install, and capable of entirely satisfactoryperformance. A preferred form of the invention comprises a desirednumber of loops of springable magnetic material which may be expanded tofit over the neck of the cathode ray tube and which will contract tosnugly embrace the walls of the tube. Ordinarily, the assembly willinclude at least two loops. However, in the event of employing amaterial having adequate magnetic propertieswithout incorporating toogreat a mass or resistance to flexing-only a single turn would have tobe employed which might extend throughout substantially 360. It is asimple matter for the installer to place the ion trap on i the neck ofthe tube and to adjust it axially and radially thereon to properlyposition the magnetic poles of the trap for optimum effectiveness.

It is an object of the invention, therefore, to provide an improved iontrap for cathode ray tubes.

It is another object of the invention to provide an ion trap which maybe inexpensively manufactured from wire or bar stock on automaticmachinery.

An additional object of the invention is that of providing a simplifiedform of ion trap which will be readily adjustable to various neckdiameters of cathode ray tubes.

It is still another object to provide an improved ion trap which issimple for the installer to position, adjust, and remove, under fieldconditions.

With these and other objects in mind, reference is had to the attachedsheet of drawings illustrating practical embodiments of the inventionand in which:

Fig. 1 is a side elevation of the neck portion of a cathode ray tube,showing one embodiment of the invention in typical operation position;

Fig. 2 is an end elevation, in section, on lines 2-2 of Fig. 1;

Fig. 3 is a View similar to Fig. 2 but illustrating the manner in whichthe diameter of the ion trap may be increased to permit its insertion orremoval on a tube;

Fig. 4 is an exploded perspective of the embodiment of Fig. 1, showingbut one of the magnetic elements;

Fig. 5 is a side elevation similar to Fig. 1, showing a second form ofthe invention;

Fig. 6 is an end elevation in section on lines 6-6 of Fig. 5; and

Fig. 7 is a view similar to Fig. 3 with respect to the second embodimentof the invention.

Referring to the drawings, Fig. 1 shows the neck portion In of a cathoderay tube such as a television kinescope, on which is mounted an ion trapll embodying one form of the present invention. The complete tube andits component focusing and deflecting mechanisms have not been shown,because they form no part of the present invention. It is to beunderstood, however, that within the neck of the tube there is providedthe usual electron gun (not shown) in which the electron beam isdeveloped and directed toward the target area or screen of the tube. Asis known, the electron beam is focused and then deflected to trace apattern on the target screen. The focusing coil and deflector means arenormally located to the right of the ion trap as viewed in Fig. 1.

In the embodiment of Fig. 1, the ion trap comprises a pluralityforexample, threesingle loop coils Ila, lib, lie, of magnetic material. Thecoils are magnetized so that each has north and south magnetic poles inidentical diametrical relationship as viewed in Fig. 2. It will beunderstood that the respective poles can be at the extremities of anydiameter about the full periphery of the coils; it is preferable,however, to have one of the poles related to a definite ref erencepoint, such as the leg portions of each of the coils, to avoid thenecessity of otherwise marking the pole positions.

Fig. 4 is representative of all of the coils. Each coil, therefore, hasits end portions in overlapping relationship, terminating in the spaced,downwardly directed, leg portions 12. The respective legs are parallelto the plane of the loop. When the leg portions are manually squeezedtogether, the coil diameter will enlarge or distort so as to provide asubstantially larger central opening.

To mount the coils in mutual parallelism, there are provided thenon-magnetic clamps or separators l3, which have channels or.passagesI311, I32), 130 to singly receive the leg :portions of the individualcoils. The channels are mutually parallel and suitably spaced to mountthe individual coils in spaced relationship such as, shown in Fig. 1.

pressed for frictional securement to" the leg por+ tions. Accordingly,the clamps are preferably tubular in form. It has been found unnecessaryto braze or otherwise permanently secure the ends of the coils withinthe blocks.

A further advantage derived by the clamps is that when the coils arevproperlyrassembled therein, each Will be distorted'substantiallyequally when the clamps are drawnintocontact with one another, asshownin Fig.v 3. The spacebetween the respective inner walls of the. clampsis such that Wh'entheyaresqueezed together tothe Fig. 3 position, theresulting enlargement'of, the. coils will permitthe unit to.be-passed-over theconnection baseof-the tube, andowhen the clamps arereleased the. coils will resilientlyv grip the, side walls of the tube.The installer may, therefore, enlarge the-effective .coildiameter atwill, to shift the trap axially or radially on thetubeneck whenadjustments are necessary.

In the embodiment .ofFigi 5, the ion: trap '20 comprises asingle-.lengthof wire orbar stock Wound as auniform diameter helixhavinga suitable number of convolutio-ns. Thewireor bar stock, like thatof the-previous embodiment, is'of springablemagnetic material,andisappropriate- 1y magnetized .after. winding sothat eachconvolutionhas mutually, aligned north andsouth poles... The. ends ofthecoil arebent oppositely outwardlyandlthen in-parallel relationshipassuggestedin .Fig. 5.tov provide the. finger pieces 2| by means of.whichthe said coil ends maybe gripped and 'moved to the Fig .7 positionto. en-

large. theeffective .coildiameter and permit its installationorremovaloverthe endof the tube, oradiustmentalong theneck thereof. In.manner similarto that described 'withrespect toFig, l, the ion trap,when the finger piecesare released, fits thetube neck snugly and inresilient engage-. ment therewith.

Thus among .others,.the several objects ofthe inventionas afore notedareachieved. Obviously numerous changes in construction and rearrangement of the parts mightbe. resorted to without departing from the spiritof theinvention as defined by the: claims.

I-claim:

l: A magneticstructure for .usein an ion-trap for resilient engagementabout the neck. of Y a cathode ray-.tube, comprising a. p-luralityofcoils of springable magnetic material, said coils being ofruniformdiameter and each magnetized with the respective magnetic poles inmutual-alignment, and-.finger piece'means at the" extremities of saidcoils bywhich the effective coil diameter may be increased uponqueezingsaid finger piece After the leg portions of the plurality ofcoils are inserted into the base clamp channels, the clamps may becrimped or com 4 means together, to relax the resilient grip of thedevice on the neck of said tube.

2. A magnetic structure for use in an ion-trap, said structurecomprising a plurality of mutually independent, permanently magnetizedcoils of springable magnetic material, each coil being characterized byangularly offset terminal portions, and a base block for receiving thesaid terminal portions of all of the coils to secure the respectivecoils with respect to each other.

3. A magnetic structure for use in an ion-trap. said structurecomprising a. plurality of individually magnetized coilsof'springablemagnetic material, each said coil being characterized by angularlyoffset terminal portions, and non-mag- .netic base block means forreceiving the said coil ends-and said base block means being arranged tomaintain the coils in parallel relationship 4. A-magnetic structure foruse in an ion-trap, said structure comprising a plurality ofindividually magnetized coils of springable magnetic material, saidcoils being of substantially equal diameter when relaxed, and the endsof each coil extending oppositely outwardly and then downwardlyeach endportion of a.coi1 being similarto the corresponding end portion of eachother coil, and a base. block to receive the-said corresponding ends,said base block being of tubular form. vand h'aving groove-formingchannels .in -its. innerwall to receive. the said, downwardly extendingcoil en'dlportions- 5..- Amagnetic structurefor use in an ion-trap, saidstructure comprising a. uniform diameter helixof springable:magneticmaterial, the convolutions. of saidhelixbeing individuallymagnetizediwiththe respective magnetic poles in mutual alignment; theends ofsaid helix extending oppositely outwardly. and thenparallel tothehelicalv axis .to. provide finger. grip portions for manually.distorting thehelix to increase'the effectiveinside diameter. thereof.

6-. A magnetic structure for use in. an ion-trap, saidstructure.comprising a-uniform diameter helix .ofspringable. magnetic material,,the convolutions of said helix being individually magnetizedfwiththerespective magnetic polesin mutual alignment, the ends. of said helixextendingoppositely. outwardly and then in mutually parallelrelationship. to provide. finger. piece means for. manually distortingthe helixto increase theeifective inside diameter thereof.

'7. In a magnetic. structure foruse in. anion: trap-asanarticle ofmanufactur.e-a,.resilient magneticelement extending substantially in theform vof.a loop-With overlappedrelatively movable. end portions, saidend portions .uponbe'ing.

shifted. serving to contract and expandthe loop.

8. Ina magneticstructure-for use in an iontrap-as an. article ofmanufacture-a clamp for application to the end of a magnetic coil whichis. to encircle. a part of a cathode raytube, said clampincludinga bodyof -material formed with a socket-to receive and retain the coil end.

9. In a magnetic structure foruse in an iontrap-as an articleofmanufacture-a clamp for application tothe ends of magnetic coils whichareto encircle a partof a-cathode ray tube, said clamp including abody-of non-magnetic material-formedwith a plurality of socketsextending parallel to and spacedifrom-"each other and each ofwhich-areto receive and retain one of the coil ends- GEORGE J. MUCI-IER;

(References onfcllowing page) REFERENCES CITED The following referencesare of record in th file of this patent:

UNITED STATES PATENTS Number Name Date Schlesinger Jan. 30, 1940Roosenstein et a1. Apr. 2, 1940 Bowie Aug. 13, 1940 Branson Feb, 24,1942 Bocciarelli Dec. 14, 1948 Wainwright Dec. 14, 1948 Torsch ..1 Feb.1, 1949 Woodbridge June 7, 1949 Kelar Jan, 31, 1950 Heppner Feb. 28,1950 Number Number

